Prosecutors going after former Goldman Sachs computer whiz Sergey Aleynikov for theft say they haven’t yet found the allegedly pilfered code on his new employers’ computers — potentially blowing a hole in their case.

According to prosecutors, the 40-year-old New Jersey resident downloaded the software ahead of taking a higher-paying gig at Teza Technologies, which hired him to build a high-frequency trading platform.

Goldman’s computer code was worth millions, and Aleynikov stole it for the “economic benefit of himself and his new employer,” prosecutors said in the stinging indictment brought against him last week.

But at yesterday’s arraignment for the amateur ballroom dancer, Assistant US Attorney Joseph P. Facciponti told US District Court Judge Denise Cote that a preliminary search of Teza’s computers hadn’t turned up any of the source code in question.

Aleynikov yesterday pleaded not guilty to charges of theft of trade secrets, unauthorized computer access and transportation of stolen property in interstate and foreign commerce. If convicted, he could get 25 years in jail. His trial has been set for Nov. 29.

Chris Gair, a lawyer for Chicago-based Teza, told The Post that no amount of searching will turn up the code “because Aleynikov did not transfer any Goldman code to Teza.” Gair added that Teza, a trading firm founded by former Citadel employees, called federal prosecutors in July — immediately after Aleynikov’s arrest — and “voluntarily offered them our computers.”

Meanwhile, the feds yesterday also said they denied Aleynikov’s request for a deferred prosecution deal.